に会っていません

haven't seen

→ に
phrase Uncommon #8,548
haven't seen The に marks the person you haven't seen or met. The phrase can also mean “haven't met.”
JA: 最近、友達に会っていません。
EN: I haven't seen my friend lately.

それ以来彼女に会っていません。

I haven't seen her since then.

私は何年もトムに会っていません。

I haven't seen Tom in years.

最近彼に会っていません。

I haven't seen him lately.

この前の日曜日以降、私は彼に会っていません。

I haven't seen him since last Sunday.

私はその後ずっと彼に会っていません。

I haven’t seen him since then.

私たちはずいぶん長い間お互いに会っていません。

We haven't seen each other in quite a long time.